Depositional models for manganese oxide and carbonate deposits of the Precambrian Sausar Group, India
Depositional models for manganese oxide and carbonate deposits of the Precambrian Sausar Group, India
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DOI：
10.2113/gsecongeo.87.5.1412
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发表时间：
1992-08
期刊：
影响因子：
5.8
通讯作者：
S. Dasgupta;Supriya Roy;M. Fukuoka
中科院分区：
文献类型：
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作者：
S. Dasgupta;Supriya Roy;M. Fukuoka
锰矿产于印度中部元古界 Sausar 群的泥质 Mansar 地层和钙质 Lohangi 地层中。锰氧化物与各种硅酸盐混合物构成了主要矿石。此外，含有或不含硅酸盐的碳酸锰-氧化物沉积物在氧化物沉积物中以孤立的透镜形式出现。岩性特征表明索萨尔群沉积物沉积在稳定的陆架环境中。从锰矿床的矿物化学属性来看，我们推测氧化矿是由富含Mn（超+2）的缺氧底水在大陆边缘涌出并与含氧的地表水混合时形成的。碳酸锰是通过在蒸发条件下与隔离池中的钙质分离反应而从氧化物中成岩衍生的。硅酸锰混合物是由于沉积过程中碎屑流入而产生的。
Manganese ores occur conformably enclosed in the pelitic Mansar Formation and the calcareous Lohangi Formation of the Proterozoic Sausar Group in central India. Manganese oxides with variable silicate admixtures constitute the predominant ores. Further, manganese carbonate-oxide deposits, with or without silicates, occur as isolated lenses in the oxide deposits. Lithologic characteristics indicate that the Sausar Group sediments were deposited in a stable shelf environment. From the mineral-chemical attributes of the manganese deposits, we propose that the oxide ores were formed when anoxic bottom water enriched in Mn (super +2) was welled up on the continental margin and mixed with oxygenated surface water. Manganese carbonates were diagenetically derived from oxides by reaction with calcareous partings in isolated pools under evaporative conditions. Manganese silicate admixtures were produced as a consequence of influx of detritus during sedimentation.